Comment 7 for bug 834037

Just passing along what I've experienced with this bug. I also posted this on
the duplicate bug (#818830) in case one of them is marked as a duplicate.

X220 i7-2620M

I experience the difference in power usage w/ 3.x kernels and setting the
i915.i915_enable_rc6=1 parameter fixes this issue while bringing back the video corruption.

The video corruption for me takes the form of light and dark grey horizontal
stripes covering the screen. It always kicks in running on battery, when the
screen is waking up from X having it off (due to lid being closed or DPMS
turning it off). If I close and reopen the lid again I can see the correct
display for a second before the stripes cover it up again. The system is
interactive and I can blindly work with the windows.

I've found that plugging in my external monitor and using xrandr to enable it
fixes the problem. I've been messing around with various xrandr commands to see
if I can come up with something that fixes the problem without having the
actual physical external monitor plugged in but have had no luck so far.